1. Field of the Invention
The present invention relates generally to electronic amusement devices and more particularly to an electronic amusement device such as a slot machine having the ability to determine a bonus payout based on a running count of tracked symbol occurrences.
2. Background of the Invention
Modern casinos offer players a wide variety of game alternatives, including table games such as craps, blackjack and poker. Slot machines, however, constitute the major source of profits for casinos. Casinos therefore constantly strive to increase the attractiveness and playability of slot machines in ways that attract and retain players.
More particularly, it is of substantial value to a casino to encourage lengthier and faster play sessions at slot machines. When a player terminates play and walks away from a slot machine, that machine often goes unused for some period of time until a new player initiates play, thereby reducing revenue from that slot machine. Further, the speed with which an active player operates a machine has a direct bearing on the profit of a machine; the faster a slot machine is played, the greater the profit that machine will generate for its owner.
One method that has been used to motivate increased play of slot machines is to generate bonus payouts dependent on cumulative effects of plays. For example, several reel slot machines manufactured by International Game Technology ("IGT") provide bonuses for the cumulative effects of spins. The game "Red, White and Blue Racing 7s" is representative of "racing" types of games, featuring a race based on a number of reel symbols obtained within a given time period. The three colors of the reel symbol "7" appear on the reels with different frequencies. When a "7" comes up on a reel, a racing character "7" of the same color advances on an animated track. When a racing character crosses the finish line, the player receives a bonus, with higher bonuses for the symbol colors of lower frequency.
Another example of a slot machine "racing" game is known wherein a group of slot machines are linked to five race cars. The cars move down a track every time a certain symbol comes up on one of the reels. If a car proceeds far enough within either a three and one-half minute or fifty-two spin period, it wins.
Slot machine racing games, such as the Red, White and Blue Racing 7s and the auto race games described above, encourage an increased rate of play. However, the excitement and the motivation last only for the limited period of the race. When the race ends, all player investment in the racing aspects of the game are lost, and the player may be motivated to cease play and search out another game.
In contrast to the racing games described above, another set of games uses accumulated reel spins to adjust different types of counting mechanisms. In such games, when a particular goal is met (e.g., a particular quantity of symbols is accumulated) a bonus is awarded.
The game "Double Diamond Mine" by IGT operates to allow players to collect diamond symbols from the three slot machine reels. The diamonds from each reel are counted and displayed by separate graphical counters. When a graphical counter indicates that it is "full," it is emptied and the player wins a bonus. Any accumulated diamonds remain in the other two graphical counters, so a player who wins a bonus still has some equity to protect by continuing to play.
In the games described above, casino operators are constrained in the amount of money that they can offer for the achievement of the bonuses because there is an inverse relationship between the payout amount and the odds of achieving the bonus payout. In order to make it economically feasible to offer a relatively high payout, the casino must set the odds for achieving the bonus payout relatively low, thereby discouraging players who "never seem to get close" to achieving a bonus. The casinos can increase the probability of winning a bonus payout, but only by decreasing the bonus payout amount, thereby significantly decreasing the player's motivation to remain at the machine.
In the IGT game "Wild Cherry Pie," whenever a Wild Cherry Pie symbol appears in the reel slot machine window--even if it's not on the payline--a cherry is added to a pie under construction on a display screen. The player wins a bonus when sufficient Wild Cherry Pie symbols have been accumulated to complete a section of the pie.
In another example of a cumulative bonus symbol type of game, AC Coin & Slot Service Company developed a series of games in which there was a time period during which a player attempted to accumulate a number of reel symbol outcomes. Three bonus payouts were provided at ten, fifteen and twenty-five coins, respectively. Each reel of the slot machine included one or more special symbols, the occurrence of which advanced the player closer to one of the three bonus levels. Upon the completion of a one-hundred second time period, the bonus session ended and the player result (i.e. the number of special reel symbols accumulated) was compared to the totals required to obtain each bonus level. Any bonus earned was paid out, and any accumulated special reel symbols were then zeroed out.
In the public-domain, Windows.TM.-based slot machine game, "Power Play Slots," players' Power-Play symbols occurring on a payout line are `collected` to add 10% to a power meter. A bonus is provided for reaching the top of the power meter. The occurrence of a Power Drain symbol voids any Power-Play symbols visible, and results in the loss of fifty percent of the accumulated power. Such a sizable setback is very discouraging to a player and may prompt the player to leave the machine.
In another public-domain, Windows.TM.-based slot machine game, "Wild Wizard Slots" by Ultisoft, the letters B, O, and X are included amongst the reel symbols. As the game is played, each letter is accumulated until its individual count goes over seven; then it is reset to zero. If the total for all three symbols reaches twenty, the player wins the bonus pool. If it reaches 21, the player wins seven times the bonus pool. After either bonus is won, the total resets to zero.
In a three reel slot machine named "X Factor," Power Point symbols are provided on each reel which function to provide a bonus multiplier. Hence the name X Factor, where the X represents the earned multiplier. The bonus multiplier increases with continued appearances of Power Points, until a conventional payout is earned. The payout is multiplied by the bonus multiplier effective at that time, and the bonus multiplier is reset to zero.
These games all suffer from several shared disadvantages. First, the games do not accumulate symbols in a manner that maintains a constant state of motivation for the player to continue play. Each game presents its own periods of quiet time during which a player may be motivated to cease play. For example, the Double Diamond Mine, Wild Wizard Slots, and Wild Cherry Pie games have periods where bonuses are awarded, groups of bonus symbols are cancelled out, and bonus play may temporarily decline. With Power Play Slots, the accumulation of symbols takes a substantial setback every time a Power Drain symbol is hit, and drops to zero when a bonus is awarded. In the AC Coin & Slot Service Company games, accumulated bonus symbols are zeroed out every one hundred seconds. In the X Factor game, the bonus multiplier is cancelled out once it hits.
It would be highly desirable to provide such a slot machine, where a player is motivated, on a consistent and ongoing basis, to prolong session play so as to avoid losing accumulated credits. Such a game would preferably avoid the pitfalls of the prior art, particularly that of permitting lulls or quiescent periods where it appears that game play can be terminated without a significant loss of accumulated credits.